Irune Indacoechea-Vega

Asphalt mixtures with high rates of recycled aggregates and modified bitumen with rubber at reduced temperature

An asphalt concrete and a very thin asphalt concrete have been designed with more than 80% of alternative aggregates (primary slag of electric arc furnace and reclaimed asphalt pavement). A modified bitumen with rubber from end-of-life tyres, and a fatty acid amide wax to decrease the manufacturing temperature were used. The process of manufacturing has been carried out in the easiest way. Both mixtures were manufactured at conventional temperature without wax (170°C), and at reduced temperature when the wax was incorporated (150°C). Their mechanical and dynamic performance was compared. The resistance against plastic deformation and the effort that has to be made for the compaction of the mixtures modified with the wax at reduced temperature did not change, but the indirect tensile strength ratio decreased. The stiffness in the mixtures with wax was slightly higher, and there were no significant differences in the resistance to fatigue, although it seemed to decrease when the wax was added.